/*********************************************************************************
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* Copyright: (C) 2025 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: time.c
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* Description: This file is print current time
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*
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* Version: 1.0.0(10/15/2025)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "10/15/2025 04:54:04 PM"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <time.h>
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/* Print struct tm information with weekday and timezone */
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void print_tm_info(const char *label, struct tm *t)
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{
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const char *weekday[] = {
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"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
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};
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printf("%s: %d-%02d-%02d %02d:%02d:%02d\n",
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label,
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t->tm_year + 1900,
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t->tm_mon + 1,
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t->tm_mday,
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t->tm_hour,
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t->tm_min,
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t->tm_sec);
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printf(" Weekday: %s\n", weekday[t->tm_wday]);
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if (t->tm_zone != NULL)
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{
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printf(" Timezone: %s\n", t->tm_zone);
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}
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else
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{
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printf(" Timezone: UTC\n");
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}
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printf(" tm_yday = %d\n", t->tm_yday);
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}
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int main(void)
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{
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time_t t;
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struct tm *tm_ptr;
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struct tm tm_local_r;
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struct tm tm_gmt_r;
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/* 获取当前时间戳 */
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t = time(NULL);
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printf("Epoch time: %ld\n\n", (long)t);
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/* localtime (非线程安全) */
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tm_ptr = localtime(&t);
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if (tm_ptr != NULL)
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{
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print_tm_info("Local time (localtime)", tm_ptr);
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}
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/* localtime_r (线程安全) */
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if (localtime_r(&t, &tm_local_r) != NULL)
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{
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print_tm_info("Local time (localtime_r)", &tm_local_r);
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}
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/* gmtime (非线程安全) */
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tm_ptr = gmtime(&t);
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if (tm_ptr != NULL)
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{
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print_tm_info("UTC time (gmtime)", tm_ptr);
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}
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/* gmtime_r (线程安全) */
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if (gmtime_r(&t, &tm_gmt_r) != NULL)
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{
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print_tm_info("UTC time (gmtime_r)", &tm_gmt_r);
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}
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return 0;
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}
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